1. Field of the Invention
The present invention relates to a waterproof case to be attached to, for example, an engine room of a motor vehicle and which is suitable for use as an electrical connection box receiving therein electrical components such as a fuse or a relay.
2. Description of the Related Art
A motor vehicle is provided with an electrical connection box arranged at an suitable location within the vehicle to supply electricity from a source to a variety of electrical equipments mounted on the vehicle. There are a wide variety of electrical connection boxes depending on a type of the vehicle. One example of such electrical connection box is disclosed in Japanese Patent Application Publication No. 2004-64872 and is illustrated in FIGS. 4 through 6 as an electrical connection box 110. As shown in the figures, the conventional electrical connection box 110 includes a waterproof case 11 arranged to receive several electrical components, and the waterproof case 11 is provide with a case body 13 made of synthetic resins, an upper cover (not shown) attached to an upper portion of the case body 13, and a lower cover 14 attached to a lower portion of the case body 13. The electrical connection box 110 is arranged to be attached to, for example, an engine room of the vehicle.
Referring to FIG. 6 which shows an enlarged cross-sectional view of the waterproof case 11, a peripheral wall 131 of the case body 13 is placed so as to overlap with a peripheral wall 142 of the lower cover 14. Thus, a space formed between the peripheral wall 131 of the case body 13 and the peripheral wall 142 of the lower cover 14 opens downward in a vertical direction, thereby preventing water flowing down along the peripheral wall 131 from entering the waterproof case 11 via the above-described space between the peripheral wall 131 and the peripheral wall 142.
However, for the above-described conventional waterproof case 11, if the waterproof case 11 is squirted with water or washing liquid, for example during car washing, there is a possibility of the ingress of the water or the liquid into the waterproof case 11. This may cause a failure in the electrical components or a leak of current or other undesirable problems.
More specifically, for example during the car wash the squirted water or the washing liquid directly hits the peripheral wall 142 of the lower cover 14, exerting a force on the peripheral wall 142. Thus, the peripheral wall 142 may be deformed inward, and this deformation may in turn causes widening of the space between the peripheral wall 131 of the case body 13 and the peripheral wall 142 of the lower cover 14. As a result, the water may enter the waterproof case 11 through that space. In view of this, there is provided a protection piece 143 arranged at the peripheral wall 142 of the lower cover 14. This protection piece 143 is arranged so as to overlap with a portion of the peripheral wall 131 of the case body 13, so that the portion of the peripheral wall 131 of the case body 13 is sandwiched between the protection piece 143 and the peripheral wall 142 of the lower cover 14. In such manner, the inward deformation of the peripheral wall 142 of the lower cover 14 due to the force exerted by the water hitting on the lower cover 14 can be prevented. Thus, the ingress of the water into the waterproof case 11 can be prevented.
However, there is still a problem that the above-described protection piece 143 cannot reliably prevent the ingress of the water into the waterproof case 11, since the water flowing on the peripheral wall 131 of the case body 13 may enter the waterproof case 11 through a space between the peripheral wall 131 and the protection piece 143 along a path indicated with an arrow Y3 in FIG. 6.